Selectable Microporous Carbons Derived from Poplar Wood by Three Preparation Routes for CO Capture.

Biomass-derived porous carbons are one kind of sustainable, extensive, and flexible carbon material for CO capture. Here, we prepared several microporous carbons from poplar wood by three preparation routes. Especially, the residues of the poplar wood after the bioethanol process were explored as precursors to prepare activated carbon by KOH and ZnCl activation. By the adjustment of the preparation routes and the optimization of the activation conditions, these porous carbons exhibited diversified morphology (sponge, nanosheets, and honeycomb structure), tunable porosity (specific surface areas: 511-2153 m/g), and narrow micropore distribution (0.55-1.2 nm). These carbons had a high CO uptake of up to 217 mg/g at 273 K and 1 bar, which was comparable with those of many N-doped porous carbons, and possessed moderate isosteric heat of CO adsorption (21.1-43.2 kJ/mol), good cyclic ability, and high CO/N selectivity (Henry's law: 44.0). The results indicated that CO uptake of these carbons was mainly decided by their micropore volume ( < 1.0 nm) at 273 K and 1 bar. This work provides an important reference for preparing promising CO adsorbents with tunable structures from similar biomass resources.